Method of producing beads



lAung. 3, 1943.

` .L...'G. ARPIN METHOD oF PRonucING BEADs' original Filed Aug. 5, 1940 l FIGLI.

FICB.

IN V ENTOR,

A R F l N LEONARD G. BY i; v I

ATTORNEY.

Reissued Aug.' 3, 1943 Leonard G. Arpln, Montclair, N. J.

Original No. 2,231,556, 'dated February 11, 1941,

Serial No. 350,550, August 3, 1940.

Application for reissue April .16, 1941, Serial No. 388,875

. 5 Claims.

My'invention relates'to themanufacture of spherical articles such as beads and marbles of all types.

Formerly such articles were generally made of glass, but in recent years the trend toward the use of plastic materials has become marked.

Plastics, such as cellulose acetate, thermosetting plastic materials or similar materials are suitable, the qualities of these plastics being well known in the art. l

I am aware ci a method of making beads in which plastic material is cast or extruded in the form of a rod, the diameter of which apprximates the diameter of the finished bead. The rod is then maintained between grinding elements, which by means of semi-circular grooves,` grind the rod so that a ball is formed for each groove on the grinder element, t is apparent that a great deal of material must be Wasted in this grinding process, viz., the material vbetween the areas required to form the balls. Furthermore, each ball must be drilled to provide the usual bead hole and this ameran tion adds appreciably to the cost oi' manufacture.

Bearing the foregoing in mind, it :ls an oh ject of the present invention to produce beads which, although ground, are accompanied by an insigniiicant waste of material in their manu.- facture.

It is also an object oi this invention to eliminate the step of drilling holes in such beads and in addition produce a bead haring a smoother and more symmetrical hole than produced by the grinding and drilling method above noted.

' long the life of the grinding elements, this fee.m

ture being attributable to the reduced amount of grinding required in the process. l

Other objects oi-my'in'vention will be appar ent from the following description, it being understood that the above general statements o the objects of my invention are intended to explain and not to limit it in any manner.

ReferringI to the drawing, Fig. 1 ls a plan view of a chain of balls as cast in the molding machine'.-

Fig. 2 is a schematic view of a grinding machine for grinding the chain of balls shown in Fig. 1.

Fig. 3 is an enlarged view illustrating the action of the grinder rolls on the chain of balls, and l lby gates I2.

Fig. 4 is an enlarged view illustrating the Iormation of the individual beads.

Referring to Fig. 1the chain of balls comprises individual balls Ill, having transverse holes Il formed therein and connected to each other The chain oi balls is molded of plastic material and is of course a positive rep-A lica of the ,mold which produces it. As one skilled in the art will easily recognize, the holes ll are formed by suitable pins inthe die which produced the chain.

The molding of the chain is accompanied by the usual Weld line which appears on the balls f whose removal carries with -it this objactionableweld line. It is essential for the succeeding operation that the gates he of exact length andthat the balls bespaced exactly at the correct distance apart.

This correct distance ls determined the grooves il? and ridges id formed on the grinding' roller Si of the grinding machine shown. schematically; in 2.

The construction of the grinding machine will he apparent to those skilied in the art and will he hrieiiy described:

The molded chains of balls arenlaced in the hopper l5 and individual chains 31nd their Way into the outlet which is controlled ha the feeder mechanism feeder mechanism is slidably arranged on the hopper outlet and the shelves il, by periodical reciprocatory motion, -reiease the chains individually, whereupon they fait 0nfand are supported by* the anvil iS.

The grinder elements comprise the grinder roller Gi and the pressure roller is. The roller l is pivotally supported on the bin 28 and pivotal motion is lent thereto by aan,I suitable'mechanism, the roller i9 swinging outwardly with the link 2i to permit a chain of balls to be deposited on the anvil i8. A' spring, not shown, causes the roller I9 'to bear against and urge the chain against the roller G which only ro- Gates and is not swung out of position,

The rollers. rotate in opposite directions but the roller IS is decidedly` slower than the roll i8, where, if necessary, it may be manually directed so that the balls I0 are mated with the grooves i3 as seen in Fig. 3.V The roller i8 thereupon swings inwardly and urges the chain against the roller G.` The ridges ill of the roller G are formed so that they extend slightly over the center line o! the ball I as indicated by the arrows in Fig. 4. These ridges `effectively grind -away the gates I2, and the grooves I3, being of.

the exact dimensions required, clear away the tolerance provided, removing therewith the weld line formed by the dies. Perfect and symmetrical beads are thereby formed which failinto the bin 20 when the roller lil again swings outwardly.

While the beads are formed with very little waste of material and without requiring the drilling of holes, they are actually far superior to beads as formedl from rods and drilled, because the drilling operation chips the bead and the bead hole is often rough and sharp.

, A bead formed according to the instant invention, however, has a. ground periphery which makes the surface perfectly smooth and a molded bead hole which avoids sharpness and roughness.` The nished bead bears distinct evidence of its manufacture in this regard.

The grinding roller G is of Carborundum or similar material of a neness that the particular iinish requires.

The grooves i3 of the grinder roher G must be alignment and thereafter grinding said chain to; y remove saidconnections;

2. A method of making spherical articles which `comprises casting a chain of balls connected to' each other bygates, said gates being operative to space said balls from each other in exact and predetermined relationship and thereafter grindi ing said chain by a grinder having grinding ele--V` ments tting said cast chain whereby said gates are removed and said balls ground to exact shape. 1

3. A method of making beads which comprises molding a chainof balls connected to each other bygates, each ball `having a beadhole'formedtherethrough by said mold and thereafter applying said chain to a grinder for removing said gates and reducing said beads to exact shape.

4. A method o making beads Vwhich comprises i moldingv a chain of aligned and uniformly spaced balls connected` to each other by uniform gates,

` each of said balls being slightly oversized to proof exact size and the reduced 'amount ofy grinding inherent in my'method conserves and prolongs the life of the grinder roller.

It is essential in my process that the ridges Il of grinder roller G and the gates I2 be identical in length. and that thegrooves I3 are maintained spaced so as nto mate exactly with the balls |B.

I have shown a preferred embodiment of my invention but it is-` obvious that numerous changes and omissions may be madeywithout def 'parting from its spirit.

I claim:

1. A method of making spherical articles which comprises casting a chain of balls connected in vide a working tolerance and having bead holes formed therethrough transverse to the axis of said chain, and thereafter grinding said chain of balls by a grinder having uniform grooves spaced according to said balls, the grinding spaces theree lof corresponding to said gates, said grooves of said grinder reducing said balls to exact diameter and removing surface imperfections and the grinding spaces between said grooves removing said gates, whereby separate beads are produced.

5. A method of making beads which comprises molding an elongated' member having a series of spaced bead holes formed transversely thereof by said mold and applying-said elongated memberto a grinder for separating said elongated.

member into individual beads, each of said beads having one of said bead holes formed diametrically therethrough.

y LEONARD G. ARPIN. 

